1. Field of the Invention
This invention relates to tension members, such as, but not limited to power lines, and, more specifically, to a tensioner structured to reduce the amount of sag in a suspended tension member.
2. Background Information
A tension member is any type of body that is substantially rigid when in tension but not substantially rigid when compressed. One of the most common types of tension member is a power line suspended between two towers or poles. Other tension members include, but are not limited to, guy wires, suspended telephone lines, cordage on a ship, or any other suspended rope, cable, cord, or chain. Tension members may be placed under an external tension, such as a guy wire used to support a tower, or the tension may be created by the weight of the tension member itself, such as the aforementioned power line suspended between two towers. With regard to the latter, a suspended tension member generally has a certain amount of sag between the two support points. The greater the length of the tension member relative to the distance between the two support points, the greater the amount of the sag. That is, given two support points set at a fixed distance from each other, a tension member of a first length, which is greater than the fixed distance, sags a set distance relative to a straight line between the two points. Another tension member having a second length that is greater than the first length will sag a greater distance relative to a straight line between the two points than the first tension member. As is known in the art, in addition to the length of the tension member relative to the distance between the two support points, the amount of sag is also controlled by various factors such as, but not limited to, the elasticity and temperature of the tension member.
The sag of a suspended tension member may be a disadvantage, such as when a power line sags to a point in proximity with a structure, tree, or another power line. While the amount of sag may be calculated, or observed, when the tension member is installed, the acceptable amount of sag may change over time. For example, a new building or other structure below the power line may be built, a tree or other foliage may grow to be too close to the power line, or the electrical capacity required of the line may change. Thus, what was once an acceptable amount of sag may become unacceptable. One option in such situations is to replace the entire tension member. This option can be time consuming and expensive.
There is, therefore, a need for a tensioner structured to take up the sag within a tension member that is installed between two points.
There is a further need for a tensioner that may be easily installed and removed.
There is a further need for a tensioner that is inexpensive.